lundahl



Jan. 31, 1956 K w. N. LUNDAHL 2,732,896

CLASSIFICATION SYSTEM FOR SHEET SORTING Filed July 22, 1950 5 Sheets-Sheet l Fig.l.

Auxiliary 8 Thyrotron Counter Switch '80 9 Auxiliary Thyrotron Mom Counter Switch Counter 52 Auxiliary I Thyrotron Counter s it Auxillciry Thyrotron Counter Switch Pulse Pulse 8 ho per Sh oper l 56 I 32 Amplifier Amplifier 26 Light l/ Phooelectric Source evlce E i l0 l6 24 9G2 Pinhole |4 Light Detector 28 source Throwout 60 $1 Mechanism WITNESSES: INVENTOR 1 WolterN.Lundohl.

Jan. 31, 1956 w. N. LUNDAHL CLASSIFICATION SYSTEM FOR SHEET SORTING 3 Sheets-Sheet 2 Filed July 22, 1950 MQXP XMQ MQQQQ WlTlil/li/SSES: 6

Jan. 31. 1956 w. N. LUNDAHL 2,732,896

CLASSIFICATION SYSTEM FOR SHEET SORTING Filed July 22, 1950 3 Sheets-Sheet 3 Fig 3.

Auxiliar r Stepping Relay Auxiliary Stepping Relay 2* Master 2'62 :gvfii sgaplping eay Auxiliary Stepping Relay Auxiliary Stepping 56 32 Relay 1 Amplifier Amplifier I5 26, i Light [6 Photoelectric lo I sourcec j 2o 24 Device I 62 i n- 1 I8 22 50 1 c ness Plnhole Light i I 9 Detector Sour/cc Throw,t l 28 Mechanis l 38' Time l Delay l l l l l WITNESSES: INVENTOR y Walter N.Lundahl.

Uni Swi Patent i 2,732,896 a Q ASS F CA ON SY TEM OR SHEET snnnnc Welter N. Landau, Hopkins, inn, assignor a) Westinghouse EleotrieCorp'oiiation, East Pittsburgh, Pa., a corporation of'lennsylvania Ap lic t July 2 1 ser 5175.3 2

18 Claims, (Cl.164- 68) The present invention relates, in general, to a classifi a isn ys m a hsst mat ria and. re pa t la y s a aii' qm t ss ng s ste r ontrollin the ejection of defective sheet steel from handling appara us. a In accordance with the prior art of which I am aware the sorting and classification of sheet material, especially 99 rolle steel nd nn d steel in lves a t eme dou waste due to the ejection .of undefective material with 11 ec'iually defective t r l 5hs ima er a Passin through a flying shear, such as in a steel mill, moves very rapidly, and in the operation of some prior art apparatus the sheet preceding and the sheet following thedefscti e sheet a equ ly ej ct with Ms- .shan isa sync r n t on sys e ar not suifis t y a e cise to throw-out only the defective material sheet and to tr nsmitths si n shs s- The =99mPQQQ 0f such system cannot be accelerated at a sufficiently high rate to accomplish this object. An electric control system l te so i good h am e t ve she s i sh wn ii Dowell Patent 2,433,685, especially in Fig. 7.

Accordingly, it is an object .of my invention to proyids a shei eri clas fyin y tem hi h wi l P 1 yi e Pos t ec on f o l t e de ecti e s ee m r a yhils ransm t n h .unds s t sh e s- ,7

. An the obj t o my e t n s to r ish n a to: matic sheet material classification system which is improved over those available in the prior art.

further object of my invention is to provide an aut mat l s fyi syst m wh ch i a oi h i ementions wasteof theprior art systems. a j A still further object is to provide an electronic systern whi h an pe a it s ifl c tspe d t si st nly the defecti shet mate while t a m t i only the ml n hsstsp Anadglitiqnal objector my invention is toproyide a classifying apparatus which will not require a reduction i-th ighfiow sp ed, f he e t m ter al while "emoveson-ly: the defective material.

A still dditi nal obje is t prov de a c ssific tion y m which Will ej c l o the de cti e mat a even when successive sheet lengths are defective. V 1' A further object of my invention is to provide a relatively simple classification apparatus which can be easily main ned and h h will ha e a l ng op r i g li e- Another object of my invention is to provide an automettle classification system which can be operated by either a pinhole detector or a thickness gauge indicator.

In general, my invention comprises the provision of i photo-cell counting apparatus (26 to provide an indicating signal after the passage of each sheet material length past a given position, and electronic amplifiers to amplify the output of said photo-cell counting apparatus and feed it to electronic counter circuits. A ai count is p ed t ra ty o fl p-f op multivibrator stages, one of said stagestor each of the sheet material lengths of sheet material between the photo-cell counting apparatus '(26) and the quality detectors (thickness gauge (12) or pin hole deteector (143%).

A pinhole detector or a thickness gauge detector or both.

act as these quality detectors and are located befQregthe shear. Theyare in turn connected to control the pegssage of any'signals through a first amplifier. A thyratron switch is connected to the output of each stage of the main counter, and controls the operation ofiene auxiliary counter. One of the latter auxiliary counters is provided for each sheet length between the algeye mentioned quality detectors and the photo-cell apparatus, and comprises four flip-flop multivibrator stages connected in a similar manner to the stages of the rhain counter, and, in addition, a switch relay is connected in the output of the fourth sta ge of each auxiliary counter}. The latter switch relays are used to control the operation of a sheet length throw-out mechanism or sorter. A second amplifier is connected between the photo cell counting apparatus (26 and all of the auxiliary counters. When a defect in the sheet material approaching the shear is detected by either the pinhole detector or th thickness gauge, a signal is sent to the first amplifi energize its screen gridu circuit. This latter energizetion allows the counting signal fromfthe photo-cell con nting apparatus (26) to pass to the main counter c i t and trigger the stages in the latter counter circu response ,to the movement of the sheet material lengths. As each st e. o t e m n un e i igs r u h negative grid bias on its respective thyratron switch is overcome to fire that thyratron switch. In the output circuit of each thyratron switch the operating winding of a circuit breaker is connected. The output signal from the photo-cell counting apparatus (26), as amplified by the second amplifier, is then fed to the input .of -respectively one of the auxiliary counter circuits throngh the now closed circuit breaker as each sheet material length passes the photo-cell detector The aforesaid cui't breaker is thus connected between the auxiliary counter andthe output of the second amplifier to gonern h Passa e o the a pl fi r Phot s c ng nnaratus (26 When one of the circuit breakers has been closed to allow the passage of the photo-cell detector counting signal to one of the auxiliary counters, e multivibrator stages of that auxiliary counter are so cessively triggered thereby to ultimately energize the i V winding onja momentary contact switch. The latter e; mentary contact switch, one of which is providedlfgr each auxiliary counter controls the operation of a out mechanism which in turn ejects the defective sheet length. Whichever of the sheet lengths between the p"; hole detector and thiclgness gauge and the photo cell detectoris defective, one of the auxiliary counters be triggered to accomplish its ejecti n by means of said throw-out mechanism. 1 have chosen for ,illust'r a tion a classification system adapted to. operate with four sheet lengths between the photo-cell detector and pinhole detector or thickness gauge.

i The novel features that Iconsider characteristi my invention are set forth with particularity in the a pended claims. The invention itself, however, bot to its organization and its method of operation, gether with additional objects and advantages thereol will best be understood from the following description of specific embodiments when read in connection the accompanying drawingsin which: V Figurel is a circuit diagram of the classification tern in which the various components are shown in bloclt d a ra r Fig. is a schematic circuit arrangement of classification system with the circuit elements included in each of the block diagrams of Fig. 1 enclosed dotted line blocks, and; i

Fig. 3 is a circuit diagram for an electromechan cal 3 classification system in accordance with a modifiedform of my invention. In the classification system shown in Fig. 1, a continuous sheet of material 10, such as cold rolled steel 'or tinned steel sheet, is fed through a thickness gauge detector 12 and a pinhole detector 14 with its associated light source 15 to a flying shear apparatus 16. The flying shear 16 cuts the sheet material into finite lengths 24. A photo-cell counting apparatus 26 with its associated light source 28 is placed the equivalent of four sheet lengths away from the pinhole detector 14 and thickness gauge 12 to detect the passage of the sheared material lengths from the flying shear 16. The output of the photo-cell detector 26 is connected to a main counter 30 through a signal amplifier 32 and a pulse shaper 34. The plate supply voltage of the signal amplifier 32 is controlled through a line connection 36 by the pinhole detector 14 and the thickness gauge 12. A time relay mechanism 38 is placed in the thickness gauge circuit and is synchronized with the speed of the flying shear 16 to allow both the thickness gauge 12 and the pinhole detector 14 to be commonly connected through the same line connection 36 to the signal amplifier 32. The main counter 30 is connected to a plurality of auxiliary counters 40, 42, 44 and 46 respectively through a plurality of thyratron switches 48, 50, 52 and 54 respectively. One of the said auxiliary counters and its corresponding thyratron switch is provided for each equivalent length of sheet material between the pinhole detector 14 and thickness gauge 12 and the photo-cell detector 26.

A second signal amplifier 56 is provided between the photo-cell detector 26 and the auxiliary counters 40, 42, 44 and 46 respectively through a second pulse shaper 58.

The main counter 30 comprises a plurality of multivibrator circuit stages of the usual flip-flop type, one of said multivibrator stages being provided for each auxiliary counter 40, 42, 44 and 46 respectively and equivalent length of sheet material between the pinhole detector 14 or thickness gauge 12 and the photo-cell detor 106 and a bias condenser 108. The anode 88 -.of

tector 26. Each of said auxiliary counters comprises four generally similar stages, and the final one of said stages is connected to operate a throw-out mechanism 60. The auxiliary counters are each commonly connected in this manner to the throw-out mechanism control apparatus 60 which governs the operation of a throw-out gate 62 which in turn is thereby placed in the path of the sheet material lengths 24 moving away from the flying shear 16. Throw-out gate 62 may be made of a suitable light material, such as aluminum, to reduce its inertia.

In Figure 2 is shown a more detailed schematic circuit diagram of the classification apparatus generally described above. The photo-cell detector 26 is shown to comprise a triode amplifier 64 having an anode 66, a cathode 68 and a control grid 70. A load resistor 72 is connected between the anode 66 and the positive terminal 74 of a suitable plate voltage supply. A photo-electric cell 76 is connected between the positive terminal 74 of said plate voltage supply and the control grid 70. The control grid is connected to ground through a resistor 78 and a negative grid bias voltage supply battery 80. The anode 66 of the photo-cell detector triode 64 is connected through a coupling capacitor 82 to the control grid 84 of a pentode amplifier tube 86 in the first signal amplifier 32. The anode 88 of the first amplifier pentode 86 is connected through a load resistor 90 to a suitable positive plate voltage supply terminal 91, and on through a pair of paralleled switches 92 and 94 and resistor 96 to the screen grid 98 of the'pentode 86. The same screen grid 98 is connected to ground through a condenser 100. The suppresser grid 102 is connected to the cathode 104, which in turn is connected to ground through a cathode resisthe pentode 86 is connected to a pulse shaper 34 through a coupling condenser 110.

The anode 66 of the photo-cell detector triode 64 is also connected to the control grid 112 of a pentode tube 114 in the second amplifier 56 through a coupling condenser 116. The same control grid 112 is connected to ground through a grid resistor 118. The anode of this second amplifier pentode 114 is connected to a suitable positive plate voltage supply terminal 122 through a load resistor 124. The screen grid 126 of this same pentode 114 is connected to the same plate voltage supply terminal 122 through resistor 128 and to ground through a grid condenser 130. The cathode 132 is connected to ground through a paralleled cathode resistor 134 and bypass condenser 136. The anode 120 is connected to the second pulse shaper 58 through a coupling condenser 138. 4

The main counter 30 comprises four stages of multivibrators 140, 141, 143 and 145 respectively, each of 'which includes a dual triode tube having a first and second cathode 142 and 144, a firstrand second control grid 146 and 148 and a first and second anode 150 and 152, respectively. The first cathode 142 of each of said dual triodes, is connected to the first pulse shaper 34. The first control grid 146 is connected to its second anode 152 through a paralleled resistor 153 and condenser 155 circuit. The first and second anodes 150 and 152 of each tube are connected to the positive terminal 154 of a suitable plate voltage supply through a load resistor 156. The first cathodes 142 of each tube are commonly connected. The second cathodes 144 of each tube are commonly connected. The second control grid 148 of each tube is connected to the first anode 150 through a paralleled'resistor 158 and condenser 160 circuit, and to ground through a grid bias resistor 162. The first and second cathodes 142 and 144 of each tube are respectively connected to ground through a cathode resistor 164. The first control grid 146 of each tube is connected to ground through a grid bias resistor 166.

The second control grid 148 of the first multivibrator stage tube 141 is connected to the second anode 152 of the fourth multivibrator stage tube 140 through a coupling condenser 168. The second control grid 148 of the second stage multivibrator tube 143 is connected to the second anode 152 of the first multivibrator stage tube 141 through a coupling condenser 170. The second control grid 148 of the third multivibrator stage tube 145 is connected to the second anode 152 of the second multivibrator stage tube 143 through a coupling condenser 172. The second control grid 148 of the fourth multivibrator stage tube 140 is connected to the second anode 152 of the third multivibrator stage tube 145 through a coupling condenser 174.

The first anode 150 of the first multivibrator stage tube 141 is connected to the control grid 176 of a thyratron tube 178 in the first control switch 48 through a coupling condenser 180. The first anode 150 of the second multivibrator stage tube 143 is connected to the con trol grid (not shown in detail) of a second thyratron 'switch'50 through a coupling condenser 182. The first a cathode 188, a control grid 176 and an anode 190. The

cathode 188 is connected to ground. The grid 176-is connected to groundthrough a grid resistor 192 and a negative bias voltage supply battery 194. The anode 190 air-sagas is. squashed to a s it bl e min l. 1 6 Qt a p siti e. ats vh c's m y ssh the vi in -8 a ir uit brl h 200. and. t e paral e contac s 202 nd 20 o a momentary contact trip, switch 206. The trip switch 206 has an operating winding 208 which is connected, to the auxiliary counter 40 for the thyratron switch 48. This winding 208 operates the momentary contact throw-out trip, switch 206 which controls the operation of the throwout mechanism 60. The four thyr atron switches 48, 5Q, 52 and 54. and auxiliary counters 40,, 42, 44 and 46 operate, a similarmanner respectively.

2 Each of the auxiliary counters 40, 42, 44 and 46 com.- prisesi our m l y bra h s e T ih'i hQ in det i for the first auxiliary counter 40 in Fig 2. Each of its four stages includes a dual triode tube 210, 212, 214'and 216 respectively connected as a Inultivibrator. Each tube has a first anode 218 and a second anode 220, a first control grid 222 and a second control grid 224 and a first cat ode, 226 and a second cathode 228. The cathodes 2 26 and 228 of each tube are connected to ground through espe t ve cathode r istors. 23.0.. h fi t n d .18 i hhhh ted to th whd. sh rc grid 2 o h ube through a paralleled resistor 232 and condenser 234 circuit second anode 220 is'connected to the first q h o id 22.2. o a h ube h s p all l sistor 236 and condenser 238 circuit. The first control grid 2 22 and second control grid 224 of each tube are respectively connected to ground through grid resistors 246. The first anode 21 8 of each tube and second anode 220 of tubes 210 212 and 214 are respectively connected to the positive terminal 196 of a suitable plate supply voltage through plate load resistors 242. The second anode 220 of the first sta e, tube 210 is connected to the second control grid 224 of the second stage 212 through a coupling condenser 244. The second anode 229. ot the seschd s age. 1 s nect he o d ontr l. rid 224 of the third stage 214 through a coupling condenser 246. The second anode 220 of the third stage 214 is connected to the second control grid 224 of the fourth stage 216 through a coupling condenser 248. The second anode 220 of the fourth stage 216' is connected to the second control grid 224 of the first stage 21 through a coupling condenser 250. In the fourth stage 216 the second anode 220 is connected to the positive terminal 196 of a suitable plate voltage supply through the rno- 'm'entary contact trip switch control winding 208. The first cathode 226 of each of the four stages is connected to a pulse shaper 8 and the anode 120 of thesecond amplifier pentode tube 114 through a coupling condenser 138 and a circuit breaker 20,0 controlled by the circuit breaker Winding 198 in the thyratron 178 plate circuit. Each of the auxiliary counters 40, 42, 44' and is similarly interconnected, and operated by respective thy ratron switches 48, 50, 52 and 54, as shown generally in Fig. 1. e

i In Fig. 3 is shown, instead of the electronicv classification system shown in Fig. l, a modified classification system using electro-rnechanical stepping relays substi tuted for the multivibrator counters previously shown and described above. The thickness gauge detector 12 and pinhole detector 14 are connected to a first electronic amplifier 32 in a similar manner to that shown in Fig. 1 The photo-cell counting apparatus 26 is connected to the first amplifier 32 and second amplifier 56 in a similar manner, also. The output of the first amplifier 32 is connected to control the operation of a master stepping relay 252. Said master stepping relay 252 controls the position of a rotary mechanical switch 254. The output of the second amplifier 56' is fed through the rotating contact 256 of said rotary mechanical switch 254 to one of a plurality of auxiliary stepping relays 25 8, 260; 262

and 264, dependent upon the position of the rotary contact 256 as determined by the master stepping relay 252. An electrical connection 270 is made between the output ofamplifier 56 and each of the auxiliary stepping relays to a lo h nh s h i als. fr sh he m ifi tche a plie o hos a ili r st' hihs e a hish-he s b initially i r hr h a i i ihh Qt q atishsl switch 254 or after said switch 254 has been moved to another auxiliary stepping relay position. The outputs of the auxiliary stepping relays 258, 266, 262 and 264 are commonly connected to the throw-out mechanism which controls the throw-out gate 62.

The exemplary illustration chosen in Figure 3 shows four auxiliary stepping relays 258, 260, 262 and 264, for operation in a modified four sheet 18, 20, 22 and 24 reject system. Between the pinhole. detector 14 and thickness gauge 12 and the photo-cell counter 26 there is a distance equivalent to four sheet lengths as cut by the, flying shear 16.

The classification system shown in Figure l operates as follows. The sheet material 10 to be cut into lengths by the flying shear 16 is first fed through a thickness gauge 12 and a pinhole detector apparatus 14. If the, thickness of the sheet material 1 0 is un sl litable or if pinhole defects are detected by the pinhole detector 14 a signal is fed to the first pentode amplifier 32 through electrical con: tacts: in the plate voltage supply circuit (see Fig, 2) of said amplifier 32. The thickness gauge 12 isconnected through a time delay circuit 38 because of the physical displacem n hs sh he i ish th t i k e au e. 12 in detecting the thickness of the sheet material n h B sitiQh of ths ihhsle d t dashing pinhole defects in the sheet niateriallfl. The time delay inechanisrn 38 is chosen to compensate for the travel time recruited. by the sheet mat rial, be e h PQ -s heet mat ia at the hiskh s gangs 1. a the p sition of he heet m tteii 9 t. 'p hq ste ts 14.

W e eithe the hishhess g n s .2 o h inhh s it e er 4 he e olta e pply i cu at h fir t s t de H i h s ene i d untin si h i s rom. e Ph 1l Q iatu r h seby mplifie and. Pass d o the mam shunt ircuit at! h o l ;v sh e? .5 h. hstsrs ount g an: p rah s 26 ives ss hh h i s ghs! si s r ime I h lshgt hs ng hs Q h shows. h s or v in fi 1 Passes. be ween it and ts. l ght our e 2.8 to a ow h light lh 2 nsrsizs the P oto-tel ,lfi- Wh he bl a e is. pl ced acro s th hade-cathode Qircuit or the fir n nt d a plifier 32 by means Qt ther th u e c nt t 94, at. block 2 hr he P hhs si hstct hotsl 2 a 11 921;. .4 (s in Fig. "2) the pulse output of the pulse shaper 34 and rst. h q a hhlihs .32 sh rss q d ng. e was i hi a l ts-se l: sh tin sah rhths 26 re As. 6 h. Pul e is f d to t Iha nul v h at st s i ucces i ely ri g r The output of the ph te tis fl e'firs fish hsie r thds smpl t 5h;- The st has sds'amPlifi r 2 s nected to control the operation of the main counter hrou h a Puls sh per". as e cl e sho e. The sss sl shtc s am li r 61s sshhes fi to tou aux liary h te 's 40 "4 an 4. th ou h ths re p e h s? hhhi j sw t h '45 9 5 and 4; whish r s est vl'y controlled by the four stages 140,141, 14? and (see Fig, 2 of the main counter 3t). s

h n a defect o l nt iifib is fil.FhiQK GSSl de e ted by ti he this th s s s hs .2 o th hhs s sisste 14, the plate'rcatho'de ci'reuit of the firstpentode amplifier 32 is energized. This allows the pulseoi itput of the pulse shaper 34, cor-responding to the counting signals from the Photo-cel tw s in hpp eths 26 19 trigger t respective th l ht ta e htths m th w e? 39- "As' ash thh ivih h sr s as '4 1 1 14% Or 45 (se F fe- 21 f he .r ai l whats; s his erssh t s ns s it tis u sti s thw h h switsht ywg 1529' 5 to. fi s.- hyre fhh w t h 48; 50. 5.1 54 fi es. it l o s the output of the second pulse shaper 58 through from the second pentode amplifier 56, corresponding to the output signals of the photo-detector 26, to pass to its respective auxiliary counter. When one of the auxiliary counters receives this pulse, its multivibrator stages are triggered in a manner well known to those skilled in the art to energize the trip winding 208 (see Fig. 2) of a momentary contact throw-out trip switch 206 (see Fig. 2). The latter switch 206 energizes the throw-out mechanism 60 of a throw-out gate 62 which in turn rejects the defective sheet lengths.

In Figure 2 is shown a more detailed schematic circuit of the apparatus shown in Figure l and above described. When either the thickness gauge 12 or the pinhole detector 14 are energized due to an unsuitable sheet thickness or pinhole detect, the screen grid circuit of the first pentode amplifier 32 is energized to allow the counting pulses from the photo-cell 76 due to the passage of sheet lengths and which are amplified in the triode amplifier 64, to pass through the first pentode amplifier 32. The output signals of the first pentode amplifier 32 pass through a pulse shaper 34 to the first anode-first cathode circuit of each multivibrator stage 140, 141, 143 and 145 of the main counter 30.

Under normal operation, when the sheet material is satisfactory in thickness and free from pinhole defects, the screen grid circuit of the first pentode amplifier 32 is not energized, and the first half (150-142) of the first multivibrator stage 141, the second 143 and third 145, and the second half (152144) of the fourth 140 multivibrator stages of the main counter 30 are conducting. When pulses are fed through the first pulse shaper 34 to the first anode-first cathode circuit of each multivibrator stage 140, 141, 143 and 145, the first half of the fourth stage 140 is triggered due to the reduction of its cathode potential by the triggering pulse. When the first half of this fourth stage 140 is conducting, its first anode 150 potential is thereby reduced to lower the second control grid 148 potential of the second half of this same stage 140 to interrupt the conduction of said second half. When the second half of the fourth stage 140 stops conducting, the potential of its anode 152 rises, which in turn increases the potential of the second control grid 148 of the first stage 141. This causes the second half of the first stage 141 to start conducting to lower the potential of its second anode 152. This second anode 152 lowered potential is reflected to the first control grid 146 of the first stage 141 to terminate the conduction of the first half. When the first half of the first stage 141 stops conducting, the potential of its anode 150 isincrcased, which in turn reflects an increased potential on the control grid 176 of the thyratron switch 48 for the first auxiliary counter 40. When the control grid 176 for the first thyratron switch 48 has this increased potential, it causes the thyratron 178 to fire to energize the circuit breaker winding 198 for the first auxiliary counter 40. When this circuit breaker winding 198 is energized, the circuit breaker contact 200 is closed to allow counting pulses from the second pulseshaper 58 corresponding to the output of the photo-cell detector 26, through from the second pentode amplifier 56 to the first auxiliary counter 40 first cathode 226 circuit. 7

vWhen the screen-grid circuit of the first pentode amplifier 32 is not energized,'the first half (218-222) of the creased to start the conduction of the first half of this stage 216. This lowers the potential of the first anode iii) 218 of the fourth stage 216 to decrease the potential of the second control grid 224 of the second half of this stage 216 to cause the second half to terminate conduction. Switch 206 is now set for an operation. The nonconduction of the second half increases the second anode 220 potential to correspondingly increase the potential of the second control grid 224 of the first stage 210 to start the conduction of the second half of the latter stage. When the second half of the first stage 210 starts conducting, the potential of the second anode 220 of this stage is decreased to correspondingly decrease the potential of the control grid 222 of the first half of the first stage and drive this half to non-conduction. A second counting pulse through contact 200 will, in the above described manner, trigger the first half of stage 210 to cause its second half to become non-conducting and in turn cause the second half of stage 212 to be triggered. A third counting pulse will cause the second half of the third stage 214 to be triggered. A fourth such pulse will cause the second half of the fourth stage 216 to be triggered. This energizes the throw-out trip switch winding 208 in the second anode-second cathode circuit of the fourth stage 216. Relay winding 208 isenergized whenever the second half of stage 216 of the auxiliary counter 40 is conducting. When the first half of this stage 216 is triggered by counting pulses and begin to conduct after the thyratron switch 48 first closes contact 200, the relay winding 208 is deenergized to remove the plate potential temporarily from anode of the thyratron 178. This terminates the conduction of thyratron 178 and resets the thyratron switch circuit for another suitable operation by its operating stage of the main counter 30. However, switch 200 is designed to remain closed long enough to allow the counting pulses from pulse shaper 58 to complete the counting cycle of auxiliary counter 40. At the completion of the counting cycle of auxiliary counter 40, a momentary contact switch operates the throw-out gate 62.

Each of the first 40, second 42, third 44 and fourth 46 auxiliary counters with their corresponding thyratron switches 48, 50, 52 and 54, respectively, operates in a manner similar to that described above with respect to the first auxiliary counter 40.

As a second pulse is fed to the main counter 30 corresponding to the passage of a second sheet length of material relative to the photo-cell detector 26, the now nonconducting first half of the first multivibrator stage 141 is triggered to cause the first half of the second multivibrator stage 143 to stop conducting to fire its corresponding thyratron switch 50 to allow the passage of counting pulses .from the second pulse shaper 58 to the second auxiliary counter 43 corresponding to the latter triggered thyratron switch 50.

The operation respecting how many auxiliary counters receive signals depends on the energization of the screengrid circuit of the first amplifier pentode 32, and thereby how many main counter 30 stages are triggered. If only one sheet length is defective the screen-grid circuit of the first pentode amplifier 32 will be energized only long enough to allow the counting signal from the photo-cell detector 26 to trigger the main counter through but one flip to thereby energize thyratron switch 48 and allow counting pulses to be applied to auxiliary counter 40. After the auxiliary counter 40 has completed one complete cycle of operation, the throw-out gate 62 is operated to eject only the defective sheet length. If in addition a second sheet is also defective the screen-grid circuit of the first pentode amplifier 32 is energized for an additional period sufficient to allow a counting signal from the photo-cell detector 26 to energize the second auixiliary counter 42 through a second stage of the main counter 30 and after a complete cycle operate the throw-out. gate 62 to eject the second sheet also. If a third and a fourth sheet length are defective, the screen-grid circuit of the first pentode amplifier 32 will be accordingly energized to eject s id th r a d our h. sh e l ng h in a s milar manure The pp r t s f re 3 oper tes in a m lar nau- 1 basi l to h ab e r ed app ra to j c detective sheet lengths, but utilizes mechanical stepping relays 252, 258., 260, 262 and 264 instead of the electronic multivibrator counters 30, 40, 42, 44 and 46, respectively. The screen-grid circuit of the first amplifier 32 is energized in a manner similar to that described with respect to Figures 1 and 2. However, the counting signals from thephoto-cell detector 26 operate the master stepping relay 252 to position the rotary mechanical switch contact 256 in one of the four shown positions. With a rotary Switch contact 256' position as shown in the diagram of Figure 3, the counting pulses from the photo-cell detector 26 are applied to the first auxiliary stepping relay 258 which would operate to correspondingly cause the ejection of a first sheet length which is defective. If a second sheet length is defective, in addition to and successive respecting the first sheet length, the first auxiliary stepping relay 258 and the second auxiliary stepping relay 260 will be energized by suitable successive positions of the rotary mechanical switch 256 If third and fourth successive sheet lengths are defective in addition to the first and second Sheet lengths, the first 25$, second 260, third 262 and fourth 264 auxiliary stepping relays will be successively energized through the rotary mechanical switch 256 positions as determined by the master stepping relay 252. As each auxiliary stepping relay issuecessively operated the throw-out gate 62 through the operation of control mechanism 60 ejects the defective sheet lengths.

While I have shown and described certain specific embodiments of my invention, many modifications there of are possible. My invention, therefore, is not to be restricted except as is necessitated by the prior art and by the spirit of the appended claims.

Iclaim as my invention: a

1. ln apparatus for classifying sheet material including shear means for cutting said sheet material into finite lengths, the combination comprising a photo-cell mechanism responsive to the movement of said finite lengths, an electronic amplifier connected to said photo-cell mechanism, a main stepping relay connected to said amplifier and responsive to the amplified signal from said photocell mechanism, a defect detector connected to control the operation of said amplifier, a throw-out mechanism for ejecting defective material lengths, and an auxiliary stepping relay connected between said main stepping relay and said throwout mechanism for controlling the operation of the latter in response to signals from the main stepping relay.

2. In apparatus for classifying sheet material, including shear means for dividing sheet material into a plurality of finite lengths, the combination comprisin a photo.- cell mechanism responsive to the passage of said material finite lengths, a first and a second electronic amplifier connected to said photo-cell mechanism, a main electronic counter connected to said first amplifier and having a plurality of stages, one of said stages for each of said material finite lengths between said shear and said photocell mechanism, a thyratron switch connected to each of said plurality of stages, a circuit breaker having a' winding connected to each of said thyratron switches, an auxiliary counter connected to each of said thyratron switches and connected between said second amplifier and said circuit breaker, a defect detector connected to control the operation of said first amplifier and the passage of signals thereby from said photo-cell mechanism'to said main counter, a throw-out mechanism connected. to each 'of'said auxiliary counters and adapted to eject defective material in response to the energization of said auxiliary counters.

3. Apparatus for controlling the classifying of material which is subdivided into a plurality of units that are moved along a predetermined path, including material separating n eansto separate those units having a predetermined property, comprising, in combination, means for producing a signal in response to said property in said material adapted to be disposed a predetermined distance along said path from said separating means which distance is equal to the space occupied by ii units along said path; means including a pickup component adapted to be disposed adjacent said separating means and adapted to be conditioned on reception of one of said signals for counting said units transmitted to said separating means when so conditioned; means actuable by at least the first counting operation of said counting means for counting said units regardless of whether or not said signals are produced and means actuable by said last-named counting means when it has passed through 11 counting operations for operating said separating means.

4. Apparatus according to claim 3 characterized by the fact that the means, including a pick-up component, includes n separate circuits actuable in succession by successive responses of said pick-up component to said units to initiate separate counting operations of the means for counting said units independently.

5. Apparatus according to claim 3 for the classifying of material which is subdivided into units to separate these units having at least two predetermined properties, a first property and a second property, characterized by first means for producing a first signal in response to said first property and second means for producing a second signal in response to said second property, said first and second means being adapted to be spaced a predetermined distance along the path of the units and being connected to transmit two signals to the means including pick-up means, the connection to said last-named means of the one of said means for producing a signal which is most remote from said separating means including time-delay means for delaying said signal by a time interval corresponding to said spacing.

6. Apparatus for controlling the classification of material moving along a predetermined path, including unitary separating means to separate out portions thereof having either or both of at least two predetermined properties, a first property and a second property, comprising in combination, a first means for producing a first signal responsive to said first property adapted to be disposed a first predetermined distance along said path from said separating means; a second means for producing a second signal responsive to said second property adapted to be disposed a second predetermined distance along said path from said separating means greater than said first. distance; means foractuatingsaid separating means; connections between said first means and said actuating means, and connections including a time delay component for introducing a time delay corresponding to the difference be- I tween said predetermined distances.

7. In apparatus for classifying sheet material which is cut into a number of separate. units and which passes along a conveyor line while it is being classified, the combination comprising a source of classification signals, sheet material unit counting means to be disposed along said conveyor line a predetermined number of sheet material units spaced from said source of signals, a first control apparatus which is conditioned by said classification signalsto respond to. said counting means, means responsive to a first of a succession of said predetermined number of said units for actuating said first control apparatus when it is so conditioned, a second control apparatus which is conditioned by said first control apparatus to respond to said counting means, when said first control means is actuated asaforcsaid, means responsive to said predetermined number of units for actuating said second control apparatus while it is conditioned as aforesaid-and a'sheet material throwout mechanism controlled by said second control apparatus. 1

8. In sheet material classification apparatus, including shear means for cutting said sheet material into finite lengths, the combination comprising, a source of classification signals for detecting defective material, a mechanism responsive to the passage of said lengths, a first counter apparatus connected to said mechanism responsive to said lengths item by item for counting the number of said lengths, said counter apparatus being unresponsive to said lengths in the absence of signals from said source, means actuable by said signal for conditioning said counter apparatus to operate to respond to said lengths, and a second counter apparatus responsive to said lengths item by item actuable by said first counter apparatus and by said mechanism for controlling the ejection of said defective material. 7

9. In sheet material classifying apparatus including a mechanism for dividing said sheet material into finite lengths, the combination comprising, a defect detecting apparatus, a first control counter, connections between said detecting apparatus and said counter for conditioning said counter to operate when a defect is detected, means responsive to individual lengths of said material for actuating said counter only while so conditioned, a second control counter, connections between said first counter and said second counter for conditioning said second counter to operate when said first counter is so actuated, means responsive to individual lengths of said material for actuating said second counter only while so conditioned, a materialthrowout apparatus for ejecting defective lengths, a normally open circuit having switch means therein for closing said circuit for actuating said throwout apparatus when closed, and means responsive to both said counters when they have been actuated a predetermined number of times for closing said switch means.

10. Apparatus for controlling a sheet material classification system including shear means for cutting said material into finite lengths, the combination comprising, a defective material detector, a sheet material length-passage detector responsive to individual lengths of sheet, a first counter circuit, an electronic amplifier connected between said material length passage detector and said first counter circuit, said counter being actuable by said length detector and said amplifier to count said sheets only when conditioned by the response of said defective-materialdetector to defective material, a second counter circuit and a switch apparatus connected to said second counter and to said first counter circuit and responsive to actuation of said first counter for rendering said second counter responsive to said length detector, said second counter when so rendered responsive to said length detector being so responsive regardless of whether or not said defective material detector responds to defective material.

11. Apparatus for controlling sheet material classification apparatus including shearing apparatus for dividing said sheet material into finite lengths, the combination comprising, a defect detector, a mechanism responsive to the movement of said'finite lengths, a main electronic counter, an electronic amplifier connected between said mechanism and said main counter for amplifying the output signals of said mechanism, means responsive to said defect detector for conditioning said amplifier to transmit amplified signals to said counter only when said detector detects a defect, an electronic switch connected to said main counter to be actuated thereby, an auxiliary counter, a second electronic amplifier connected between said mechanism and said auxiliary counter for amplifying the output signal of said mechanism, means responsive to said switch when it is actuated for conditioning said second amplifier to transmit signals to said auxiliary counter and classification means responsive to said auxiliary counter.

12. In apparatus for classifying moving sheet material including shear means for cutting said sheet material into a plurality of finite lengths, the combination comprising, a defect detector disposed to respond to defects in said material, a mechanism responsive to the movement of said r 12 finite lengths, a main electronic counter having a plurality of stages, one of said stages for each of a predetermined plurality of material finite lengths, means connected to said detector and responsive to the detecting signals of said detector for conditioning said counter to operate to produce a signal on the detection of a defect in said material, a plurality of thyratron switches connected to said main counter stages, one of said switches for each of said main counter stages, a plurality of auxiliary electronic counters, one of said auxiliary counters connected to each of said switches for operating in response to said signals from respectively one of said main counter stages to count said finite lengths, and a throwout mechanism for ejecting defective sheets connected to each of said auxiliary counters. i

13. In classifying apparatus for moving sheet material including shear means for cutting said sheet material into finite lengths, the combination comprising, a mechanism responsive to the movement of said finit lengths and physically located away from said shear means a distance substantially equivalent to an integral number, n, of said finite lengths, an electronic amplifier connected to said mechanism, a main electronic counter connected to said electronic amplifier for responding to the output of said mechanism, said main counter having 11 difierent output terminals at which signals appear in succession for successive responses of said counter to said amplifier, a defect detector disposed to respond to defects in said material and connected to said amplifier and adapted to control the operation of said amplifier so that said-amplifier causes said counter to produce a response on the detector of a defect, n auxiliary electronic counters, and n thyratron switches, one of said switches respectively connected between each of said auxiliary electronic counters and a corresponding one of the n terminals of said main electronic counter, means for actuating each of said auxiliary electronic counters through the switch to which it is connected in response to a signal on said terminal to which it is connected to count said finite lengths, and a throwout mechanism for ejecting defective sheets connected to each said auxiliary counter.

14. In classifying apparatus for moving sheet material including a shear means for cutting said sheet material into finite lengths, the combination comprising a mechanism responsive to the movement of said finite lengths and adapted to be physically located away from said shear means a distance substantially equivalent to an integral number, n, of said finite lengths, an electronic amplifier connected to said mechanism, a main electronic counter connected to said electronic amplifier for responding to the output of said mechanism, said main counter having it ditferent output terminals at which signals appear in succession on successive responses of said counter to said amplifier, a defect detector disposed to detect defects in said material and connected to said amplifier and adapted to control the operation of said amplifier so that said amplifier causes said counter to produce a response on the detection of a defect, n auxiliary electronic counters, n thyratron switches, one of said switches respectively connected between each of said auxiliary electronic counters and a corresponding one of said terminals of said main electronic counter, means for actuating each of said auxiliarycounters to count said finite lengths in response to a signal on said terminal to which it is connected, and a throw-out mechanism for ejecting defective material lengths connected to each of said auxiliary counters.

15. In apparatus for classifying moving sheet material, including shear means for cutting said sheet material into finite lengths, the combination comprising, a photo-cell mechanism for responding to the movement of said finite lengths, a first electronic amplifier connected to said photo-cell mechanism, a second electronic amplifier connected to said photo-cell mechanism, a main electronic counter connected to said first amplifier 'for responding to the amplified signal from said photo-cell mechanism, a

13 defect detector disposed to respond to defects in said material and connected to said first amplifier for conditioning it to conduct said s gnal to said main electronic counter on the occurrence of a defect in said sheet, an auxiliary electronic counter connected to said second amplifier, an electronic switch connected between said auxiliary electronic counter and said second amplifier and operated by said main counter when it responds as aforesaid to condition said auxiliary counter to respond to said second amplifier and count a predetermined number of said finite lengths when so conditioned, and a throwout mechanism for ejecting defective material lengths connected to each auxiliary counter.

16. In apparatus for classifying moving sheet material, including shear means for cutting said sheet material into finite lengths, the combination comprising a photo-cell mechanism for responding to the movement of said finite lengths, a first electronic amplifier connected to said photo-cell mechanism, a second electronic amplifier connected to said photo-cell mechanism, a main electronic counter connected to said first amplifier for responding to the amplified signal from said photo-cell mechanism, a defect detector connected to said first amplifier for conditioning said main counter to conduct said signal to said main electronic counter on the occurrence of a de feet in said sheet, an auxiliary electronic counter connected to said second amplifier, an electronic switch operable by said main counter when it responds as aforesaid to condition the operation of said auxiliary electronic counter by said second amplifier and count a predetermined number of said lengths when so conditioned, and a throw-out mechanism connected to said auxiliary electronic counter responsive to its counting of said lengths for ejecting defective material.

17. The apparatus substantially as specified in claim 16, and a momentary contact switch connected between each of said auxiliary counters and said throwout mechanism, each said contact switch being actuable to actuate said throwout mechanism when its associated counter responds to said predetermined number of said lengths.

18. In apparatus for classifying moving sheet material including a conveying line through at least a portion of which said material is transmitted in finite lengths, the combination comprising, a defect detector disposed to respond to defects in said material, a mechanism responsive to the movement of said finite lengths, said mechanism being disposed in said portion of said line a predetermined number of said lengths from said detector, a main electronic counter having a plurality of stages, one of said stages for each of said predetermined number of finite lengths, means connected to said detectors and responsive to said detector for conditioning said main counter to operate on the occurrence of a defect in said material, a plurality of thyratron switches connected to said main counter stages, one of said switches for each of said main counter stages, and a plurality of auxiliary electronic counters, one of said counters connected to each of said switches for operating in response to signals from respectively one of said main counter stages to count said sheet, and a throwout mechanism for ejecting defective material lengths connected to each auxiliary counter.

References Cited in the file of this patent UNITED STATES PATENTS 2,047,221 Pechy July 14, 1936 2,146,581 Kaufman Feb. 7, 1939 2,194,325 Rhea Mar. 19, 1940 2,229,638 Chamberlin Jan. 28, 1941 2,244,826 Coz June 10, 1941 2,363,577 Dexter Nov. 28, 1944 2,410,156 Flory Oct. 29, 1946 2,433,685 Dowell Dec. 30, 1947 2,566,246 Peters Aug. 28, 1951 

